Make configuration files available (#30)

lib/youplot/command.rb

@@ -40,6 +40,24 @@ module YouPlot
         return
       end
 
+      # config command
+      if @command == :config
+        if ENV['MYYOUPLOTRC']
+          puts "config file : #{ENV['MYYOUPLOTRC']}"
+          puts parser.config.inspect
+        else
+          puts <<~EOS
+            You don't have a config file. The default config file paths are:
+            ./.youplot.yml, ./.youplotrc, ~/.youplot.yml, ~/.youplotrc
+            You can specify a config file with the environment variable MYYOUPLOTRC.
+            File format is YAML. For example:
+            width : 40
+            height : 20
+          EOS
+        end
+        return
+      end
+
       # progressive mode
       if options[:progressive]
         stop = false

lib/youplot/parser.rb

@@ -9,7 +9,8 @@ module YouPlot
     class Error < StandardError; end
 
     attr_reader :command, :options, :params,
-                :main_parser, :sub_parser
+                :main_parser, :sub_parser,
+                :config_file, :config
 
     def initialize
       @command = nil
@@ -28,6 +29,54 @@ module YouPlot
       )
 
       @params = Parameters.new
+
+      if @config_file = find_config_file
+        ENV['MYYOUPLOTRC'] = @config_file
+        @config = read_config_file(config_file)
+        configure(config)
+      end
+    end
+
+    def candidate_paths
+      paths = []
+      paths << ENV['MYYOUPLOTRC'] if ENV['MYYOUPLOTRC']
+      paths << '.youplot.yml'
+      paths << '.youplotrc'
+      paths << File.join(ENV['HOME'], '.youplotrc') if ENV['HOME']
+      paths << File.join(ENV['HOME'], '.youplot.yml') if ENV['HOME']
+      paths
+    end
+
+    def find_config_file
+      config_file_path = nil
+      candidate_paths.each do |file|
+        path = File.expand_path(file)
+        if File.exist?(path)
+          config_file_path = path
+          break
+        end
+      end
+      config_file_path
+    end
+
+    def read_config_file(path)
+      require 'yaml'
+      YAML.load_file(path)
+    end
+
+    def configure(config)
+      option_member = @options.members
+      params_member = @params.members
+      config.each do |k, v|
+        k = k.to_sym
+        if option_member.include?(k)
+          @options[k] = v
+        elsif params_member.include?(k)
+          @params[k] = v
+        else
+          raise Error, "Unknown option/param: #{k}"
+        end
+      end
     end
 
     def create_base_parser
@@ -277,6 +326,8 @@ module YouPlot
           options[:color_names] = v
         end
 
+      when :config
+
       else
         error_message = "uplot: unrecognized command '#{command}'"
         if YouPlot.run_as_executable?